For

Well-designed, lots of power, simple to use

Against

Quite expensive, heavy

Oh my, what a name. It's hard to deny that Mophie has a penchant for the verbose when it comes to naming things. It's good then, that its devices are so solid, and have rescued us from some very deep holes in the past.

The Powerstation Duo is the latest in a long line of such emergency battery packs. But it's a new style now, with a simpler way of working - not that the old ones were hard to use - and it all adds up to one of the most stylish and useful devices a geek can have in their bag-o-tech.

Design

There's no getting away from it - the Duo is a chunky monkey. But that size is managed with a pretty decent amount of rather lovely styling. The matt-black finish has a nice feel to it, and the silver sides give it a hint of iPhone around the edges. It is without doubt the best-looking portable battery you can buy.

On the front, there's a logo and a series of LEDs - although the LEDs are completely invisible for most of the time, springing into life only when you press the only button on the unit, on one of the edges. It's hard to say which edge, we think it's either the right, or bottom one, but that depends how you hold it!

You'll also find three sockets. Two USB outputs, and one USB input. The input is used for charging, the two outputs can charge two devices at the same time. This is very helpful indeed if two of you have managed to run out of power, or all your devices have died.

Charge anything

Good news. The 6000mAh battery in this Duo is capable of charging most phones three times from flat. That's pretty impressive.

It's also more than enough to charge an iPad or iPad2 from flat, and several other tablets too. Things get a bit more tricky when it comes to the "new iPad", which has a stonking 11,000 mAh battery to keep that screen running. You will be able to top it up though, which will give you some more valuable use. Handy on very long plane journeys.

In the past, we've had some problems with external power packs charging our original Samsung Galaxy Tab. We tested the Duo with new 10.1-inch Tab, and the old 3G 7-inch. The 10.1 charged with no problems at all. The 7-inch was happy to charge when turned off, but refused to accept that it was charging when turned on. Not, perhaps, a massive problem, but still annoying. This isn't Mophie's fault, and the good news is that everything else charges well with no fuss.

So simple

Also good news is that Mophie has taken some care to address one of the problems of the previous model. Before, you needed to press the button to start it charging. Now, the button only tells you how much charge you have, and anything plugged in will start charging instantly.

No doubt there will be some who preferred the old system; we suppose being able to chose when the charge happened was quite handy, but we don't think anyone will really miss it.

Verdict

It's predictable, but Mophie kit always works well. We think the design of this powerstation is fabulous and it matches the functionality, which is incredible and will no doubt get you out of all sorts of trouble.

We love that it's got two outputs too, as there have been plenty of times where we've needed to charge two things at the same time. And the capacity here means you should be able to get a couple of different gadgets running again before it goes flat.

At £90, it's not all that cheap, but for the pure power on offer here, we can see these being very popular. And so will anyone who produces one at a festival, or on a long flight.